Platycephalus richardsoni Castelnau, 1872

Imamura, Hisashi, 2015, Taxonomic revision of the flathead fish genus Platycephalus Bloch, 1785 (Teleostei: Platycephalidae) from Australia, with description of a new species, Zootaxa 3904 (2), pp. 151-207 : 183-186

Platycephalus richardsoni Castelnau, 1872

Common English name: Tiger flathead ( Figs. 23–24 ; Fig. 9 )

Platycephalus richardsoni Castelnau, 1872: 82 (type locality: Melbourne markets, Vic, Australia); McCulloch, 1929: 400; Last et al., 1983: 333, fig. 28.21; Paxton & Hanley, 1989: 469; Grant, 2004: 188, unnumbered pl.; Hoese et al., 2006: 943; Imamura, 2006: 305, tab. 1; Gomon, 2008: 520, unnumbered fig.

Neoplatycephalus grandis Castelnau, 1872: 87 (type locality: Melbourne markets, Vic, Australia); McCulloch, 1929: 402.

Platycephalus macrodon Ogilby, 1885: 226 (type locality: Port Jackson, NSW, Australia); McCulloch, 1929: 401.

Neoplatycephalus macrodon: Whitley, 1931b: 159 .

Neoplatycephalus (Colefaxia) macrodon: Whitley, 1935: 249 .

Neoplatycephalus richardsoni: Whitley, 1964: 57 ; May & Maxwell, 1986: 272, unnumbered fig.; Hutchins & Swainston, 1986: 127, fig. 197; Knapp, 1991: 29, tab. 1; Kuiter 1993: 101, unnumbered fig.; Kuiter, 1994: 518, fig. 461.

Material examined. 21 specimens (91.6–461 mm SL, from southeastern Australia): AMS B.6541, holotype of Platycephalus macrodon Ogilby, 1885 , 281 mm SL, Port Jackson, NSW; AMS E. 581, 165 mm SL, Oyster Bay, Tas (42.7°S, 148.1°E), date unknown; AMS E.3013, 2 specimens, 174–212 mm SL, Bass Strait, between Gabo and Babel Islands, date unknown; AMS I.23871-002, 194 mm SL, 4 miles off Whale Beach, NSW (33°37’S, 151°22’E), 54 m depth, 10 Oct. 1976; AMS I.26026-001, 266 mm SL, off Clarence River, NSW (29°26’S, 153°26’E), 11 Oct. 1985; AMS I.33329-002, 461 mm SL, Norah Head, NSW (33°17’S, 151°35’E), 1984; AMS I.40292-001, 231 mm SL, off Bermagui, NSW (36°23’S, 150°21’E), 428–468 m depth, 2 May 2000; AMS IB. 507, 440 mm SL, Wineglass Bay, Tas (42°10’S, 148°18’E), 18 June 1940; AMS IB. 7599, 379 mm SL, AMS IB. 7600, 310 mm SL, AMS IB. 7602, 321 mm SL, Lakes Entrance, Vic (37°53’S, 148°00’E), 1966; CSIRO 3534-09, 246 mm SL, south of Disaster Bay, NSW (37°23’S, 149°58’E – 37°22’S, 149°58’E), 31–36 m depth, 12 Aug. 1993; CSIRO A 1612, 91.6 mm SL, 3 miles NE of Brush Island, NSW (35°32’S, 150°25’E), 25 Jan 1946; CSIRO A 1614, 113 mm SL, Eden, NSW (37°04’S, 150°56’E), 90 m depth, 28 Apr. 1953; CSIRO CA 135, 323 mm SL, Sydney fish market, NSW, 5 July 1977; NMV A 3786, 226 mm SL, 24 km southwest of Lakes Entrance, eastern Bass Strait, Vic (38°03’S, 147°50’E), 25–45 m depth, 1 Oct. 1983; QM I. 22311, 307 mm SL, Eden, NSW (37°04’S, 149°55’E), 14 Aug. 1985; QM I. 22302, 365 mm SL, QM I. 22307, 349 mm SL, Lakes Entrance, Vic (37°53’S, 148°E), 14 Aug. 1985.

Diagnosis. A species of Platycephalus with the following combination of characters: second dorsal- and analfin rays usually 14; caudal-fin rays 13; pored lateral-line scales 65–74; gill rakers 2–4 + 10–13 = 12–17; orbital diameter 18.4–24.1% HL; interorbital width 10.1–15.7% HL; postorbital length 49.7–56.2% HL; suborbital width 4.9–9.4% HL; occipital and lower half of suborbital regions scaled in larger specimens; margin of interopercle smooth; one or two large caniniform teeth anteromedially on upper jaw; all or most pored lateral-line scales usually with two pairs of sensory ducts and exterior openings posteriorly; fleshy sensory tubes from suborbitals and preopercle not covering cheek region; swimbladder present; abdominal cavity dark brown or black.

Description. Counts and measurements shown in Table 9.

Holotype of P. macrodon Non-types

AMS B.6541 n = 20 SL (mm) 281 91.6–461 Counts:

D 1 I + VIII + 0 I + VII–VIII + 0–I

(often I + VIII + 0) D 2 14 13–14 (usually 14) A 14 13–14 (usually 14) P1 2 + 10 + 8 = 20 1–2 + 9–12 + 7–8 = 19–22

(usually 20) C 13 13

LLS (spines) 70 (3) 65–74 (1–2) OBS – 81–95 GR 3 + 11 = 14 2–4 + 10–13 = 12–17 As % SL:

HL 33.3 34.1–36.2 PDL 34.3 34.4–37.6 LD1B 21.7 16.4–22.2 LD2B 32.5 30.0–33.1 LAB 33.4 30.2–35.1 SNL 9.1 8.8–10.3 OD 6.7 6.4–8.6 UJL 12.3 12.6–14.3 LJL 17.0 16.5–19.1 IW 4.4 3.6–5.5 POL 17.8 17.2–19.3 SW 2.0 1.7–3.2 P1L 16.0 14.6–18.0 P2L 23.8 21.9–26.1 CL 15.6 15.1–19.3 As % HL:

SNL 27.2 26.0–28.9 OD 20.2 18.4–24.1 UJL 36.8 36.9–39.9 LJL 51.2 48.5–53.4 IW 13.2 10.1–15.7 POL 53.4 49.7–56.2 SW 6.1 4.9–9.4

Snout, interorbit and occipital region scaled; lower half of suborbital region naked in 165 mm SL or smaller specimens, scaled in larger specimens; area anteroventral to eye naked. Interorbit narrower than orbital diameter. Upper iris lappet simple, weakly pointed; lower absent. Nasal spine usually absent, rarely one spine present in some specimens. Preorbital spine present in smallest (92 mm SL) specimen, absent in larger specimens. One suborbital spine present below posterior margin of eye in 165 mm SL or smaller specimens, absent in larger specimens (except in 379 mm SL specimen with two spines below posterior margin of eye). Three preopercular spines present; middle spine usually slightly longer than uppermost spine (more than twice length in some specimens, but not reaching opercular margin); lowermost small. Supplemental preopercular spine usually absent (present in 93 mm and 307 mm SL specimens). Interopercular flap absent; margin of interopercle smooth. Maxilla usually not reaching, or reaching just beyond anterior margin of pupil (to middle of eye in some specimens). Upper jaw with one or two large caniniform teeth anteromedially. Palatine teeth in two rows, villiform or small conical in outer row, small to moderate caniniform in inner row. Vomerine teeth in one row anteriorly, one or two rows posteriorly, becoming larger posteriorly. All or most pored lateral-line scales usually with two pairs of sensory ducts and exterior openings posteriorly, some scales sometimes with one, three or four pairs of ducts and openings. Fleshy sensory tubes from suborbitals and preopercle not covering cheek region. Posterior tip of pelvic fin reaching from anus to base of third anal-fin ray. Posterior margin of caudal fin mostly straight in smaller specimens, slightly concave in larger specimens. Swimbladder present.

Color in alcohol. Ground color of head and body reddish-brown, pale or dark brown above, paler brown below. Side of body with or without a single row of purplish spots tending to form a band, or with a dark brown or purple band. First and second dorsal fins with distinct or indistinct pale brown to brown spots. Pectoral fin dusky, upper portion with brownish spots tending to form bands; lower margin of pectoral fin paler. Pelvic fin pale to dark brown; lower margin of fins paler. Anal fin pale or with melanophores along rays. Caudal fin dusky, or brown to dark brown; upper margin with or without indistinct pale brown or brown spots. Abdominal cavity dark brown or black.

Distribution. Known from southeastern Australia, from off Clarence River, NSW (29°26’S) to Investigator Strait, SA (137°10’E), including Vic and Tas, on the continental shelf in depths from ca. 10 to 428 m (e.g., May & Maxwell, 1986; Hoese et al., 2006; Gomon, 2008; this study).

Size. Maximum length 60 cm SL ( Gomon, 2008). The largest specimen examined during the present study was 461 mm SL (caudal fin broken).

Remarks. Platycephalus richardsoni is most similar to P. conatus , but differs in having 12–17 gill rakers in total and all or most pored lateral-line scales usually with two pairs of sensory ducts and exterior openings posteriorly (see Remarks under P. conatus ). The latter character also distinguishes P. richardsoni from other species of Platycephalus characterized by pored lateral-line scales usually with a single pair of sensory ducts and exterior openings.

Although Paxton & Hanley (1989), Kuiter (1994) and Hoese et al. (2006) considered P. mortoni Macleay, 1883 to be a junior synonym of P. richardsoni, Imamura (2013a) found the former to be conspecific with Platycephalus fuscus Cuvier in Cuvier & Valenciennes, 1829. In contrast, the junior synonymy of Neoplatycephalus grandis Castelnau, 1872 under P. richardsoni , as already pointed out by several authors ( Paxton & Hanley, 1989; Kuiter, 1994; Hoese et al., 2006), is reconfirmed here, both nominal taxa having “several arborescent tubes” on the lateralline scales (see original descriptions of both species by Castelnau, 1872). Unfortunately, the whereabouts of the type specimens of P. richardsoni is unknown at present and the syntypes of N. grandis were apparently lost (e.g., Hoese et al. 2006).

Platycephalus macrodon ( Fig. 24 ) was also regarded as a junior synonym of P. richardsoni by Paxton & Hanley (1989), Kuiter (1994) and Hoese et al. (2006). This synonymy is supported here due to the holotype of P. macrodon agreeing closely with the latter in pored lateral-line scale characteristics, and having no remarkable departures from the counts and proportional measurements accordied to P. richardsoni ( Table 9).

Figures

FIGURE 9. Dorsal view of lectotype of Platycephalus caeruleopunctatus, AMS I. 3163, 291 mm SL, Port Jackson, NSW.

FIGURE 23. (A) Dorsal and (B) lateral views of Platycephalus richardsoni, AMS IB. 7600, 310 mm SL, Lakes Entrance, Vic.

FIGURE 24. Dorsal view of holotype of Platycephalus macrodon, AMS B. 6541, 281 mm SL, Port Jackson, NSW.